2022-01-31

UTAPwiki/セミナー/初期宇宙・相対論速報

Title: Transport coefficients from the linear response theory and its application to cosmology †

Speaker:Kohei Kamada †

Abstract:
Transport phenomenon is of interest for the statistical mechanics and has been extensively
studied in the broad range of the fields of physics. In particular, the transport coefficients
that relate the flow of the physical quantities and the parameters of the system is important
to follow the evolution of the system in a consistent way. In cosmology, the evolution of
the particle number densities with their interactions and magnetohydrodynamics can be
understood as the transport phenomena. In these cases, the transport coefficients are
identified as the scattering rate, electric conductivity, viscosity, and so on.
In this talk, I will introduce the way to calculate these transport coefficients from
the linear response theory with the quantum field theory. I will derive the formula to estimate
the electric conductivity and the kinetic equation for the spontaneous baryogenesis,
which has only been intuitively given.

References:
[1] D. Zubarev “Nonequilibrium Statistical Thermodynamics” 1971, Nauka, Moskow
[2] A. Hosoya, M. Sakagami, M. Takao, Annals of Physics 154, 229-252, 1984
[3] V. Domcke, Y. Ema, K. Mukaida, M. Yamada, JHEP08 (2020) 096